Circuit breakers, sometimes referred to as circuit interrupters, include electrical contacts that contact each other to pass current from a source to a load. The contacts may be separated in order to interrupt the delivery of current, either in response to a command or to protect electrical systems from electrical fault conditions such as current overloads, short circuits, and low level voltage conditions.
In circuits where the current or voltage is sufficiently high, opening the contacts in a circuit breaker can create an arc. To avoid this result, circuit breakers may use an insulated gas, oil, or a vacuum chamber in order to extinguish the current and the arc. Vacuum circuit interrupters include a separable pair of contacts positioned within an insulated and hermetically sealed vacuum chamber. The chamber contains the vacuum and serves as a housing for the contacts and other components. Typically, one of the contacts is moveable and the other is fixed with respect to the housing, although in some vacuum interrupters both contacts may be moveable.
Vacuum circuit interrupters typically require equipment of substantial size in order to move the moveable contact and shield equipment from arc splatter. This can contribute to high cost, and it can limit the ability to use a vacuum interrupter in low and medium voltage applications. In addition, the use of vacuum circuit interrupters poses challenges in medium voltage applications, which require a relatively high opening speed and response time.
This document describes methods and systems that are intended to address some or all of the problems described above.